The problem with conventional golf clubs and particularly but not necessarily limited to non-putting type clubs, is that they are not well-designed from an engineering standpoint. This is primarily due to the fact that golfers governing bodies place restrictions and/or limitations on all aspects of the club design since their mandate is to preserve the game of golf rather than to perfect it. The most serious drawback concerns the restriction that the shaft must be connected to the club head at or near the heel of the club head. Since the majority of the mass of the club head and, hence, the center of gravity, is offset from the point of application of the swing force, i.e. the shaft connection, when the club is swung, inertia and air resistance acting on the club will tend to cause a rotation of the club head about the shaft, a phenomenon which will be referred to herein as "self-torque". This rotation of the club head and, hence, the club face (being "opens", causes the ball to leave the club face not at a right angle to the swing path. Not only does the golfer have to ensure an accurate swing path, but he must also compensate for self-torque induced problems. To complicate matters, the different clubs in a set of conventional clubs have offsets of different magnitudes, making it more difficult to adjust from club to club. In order to reduce the amount of self-torque, manufacturers are forced to provide shafts of higher torsional stiffness and, hence, of generally greater weight which, for a given club weight, will result in less weight available for selective use in the club head where the weight is most needed. A further drawback is that the ratio of width to length of the club head is required to be one or more, i.e. the club head must be wider than it is long.
The offset of the center of gravity from the shaft axis also causes problems with respect to the lie of the club. During downswing, the centrifugal force acting through the center of gravity of the club head, causes the shaft to bend downward, resulting in a one or two degree change in the lie of the club, as shown in FIG. 2, depending on the shaft flex and head speed. This happens because the center of mass or center of gravity of the club head is not in line with the centerline of the shaft in the swing plane.
Yet another drawback to conventional clubs is that, due to their design, almost the entirety of material devoted to the club head goes into ensuring the head is of sufficient strength to resist the impact of the ball, leaving precious little material for strategic placement or specialty weighting purposes. Where a larger club face or "sweet-spot" on the club face is desired, even more of the material must be devoted for structural purposes. If the overall weight of the structural material in the club head could be reduced, more weight would be available for selective disposition. Any such weight which can be freed-up, described hereinafter as "free available weight", could be used at the discretion of the manufacturer, for example, to increase the size of the sweet spot and/or the size of the club face, to compensate for habitual slices or hooks and high or low flight paths, and to provide custom clubs with a precise loft and lie to match individual needs.
It would, therefore, be greatly beneficial to have a golf club which practically eliminates this problem of self-torque. By ensuring the center of gravity is generally in-line with the shaft in the swing direction, inertia-induced self-torque can be mire. To most golfers, this would serve to reduce the number of errant shots. To the manufacturer, this would permit less torsionally rigid and, hence, lighter shafts to be used, thereby affording more free available weight for exploitation and, ultimately, an even better club for golfers. Since all clubs of the set could be designed similarly, there would be no requirement for the golfer to make adjustments from club to club to compensate for the differences in self-torque as is the case with a set of conventional clubs.
To further assist the golfer, it would be advantageous to provide a golf club which assists in self-aligning with the trajectory of the swing path to further ensure the club face remains substantially perpendicular ("square") at the point of contact.
It would also be beneficial to maximize the ball contact area of the club while maintaining the same frontal area (or air resistance) of the club head as conventional clubs. Conventional clubs have a frontal area which is significantly greater than the area of the hitting face and considerably greater than the area of the sweet-spot. For example, conventional clubs typically provide a substantially-sized hosel connecting the club head to the shaft which not only consumes club head material, resulting in less free available weight, but which also increases the frontal area of the club, and which increased frontal area is not useful hitting surface. It would, therefore, be advantageous to have a club head in which all of the frontal area of the club serves as the club face. In addition, it has been determined through research that the distribution of contact locations of the ball on the club face over a number of hits is roughly elliptical about the center of the club face. It would, therefore, be beneficial to provide a club face which reflects this type of distribution such that practically the entire club face is useful, hitable surface.
Lastly, in order to further assist the golfer, it is desired to provide a club which could compensate for striking the ball off-center with respect to the face of the club.